Guianacara (Guianacara) dacrya, Arbour & López-Fernández, 2011

Guianacara (Guianacara) dacrya View in CoL , new species

Figs. 2-6 View Fig View Fig View Fig View Fig View Fig

Holotype. UG/CSBD 1666 , (ex. ANSP 177130), 79.2 mm SL, Guyana, Potaro-Siparuni (Region 8), Water Dog Falls, Burro Burro River , Essequibo Drainage , 04º40’48”N 58º50’46”W, 20 Nov 1997, E. McBirney, W. Prince & D. Jaferally. GoogleMaps

Paratypes. Guyana, upper Takutu-upper Essequibo (Region 9): ANSP 179073 , 1, 87.1 mm SL, Yuora River , Takutu-Branco drainage , 6.7 km NE of Karasabai on road to Tiger Creek village, 04º03’14”N 59º29’07”W, 31 Oct 2002, M. H. Sabaj, J. Armbruster & M. Thomas; GoogleMaps ROM 85732 , 13, 20.5-48.9 mm SL, Old Lady Pond, Essequibo drainage , 03º36’48.3”N 59º40’33.9”W, 3 Feb 2009, E. Holm, D. Taphorn, G. Orti, K. Sugrim, C. Sugrim, C. Bernard & C. Lopez; GoogleMaps ROM 85724 , 1, 51.2 mm, Rupununi River , Essequibo drainage , near Yupukari, 03º34’34.3”N 59º20’36.6”W, 7 Feb 2009, K. Winemiller, C. Montana, M. Tobler, G. Orti & R. King; GoogleMaps ROM 85888 , 1, 76.9 mm, Rupununi River , Essequibo drainage , at Dadanawa, 02º49’54”N 59º31’41.2”W, 31 Jan 2009, H. López-Fernández, C. Bernard, K. Winemiller & D. Taphorn; GoogleMaps ROM 85772 , 7, 20.1-95.9 mm SL, Pirara River , Takutu-Branco drainage , 40 km N of Lethem, 03º37’17.3”N 59º40’29.4”W, 3 Feb 2009, H. López-Fernández, C. Bernard, K. Winemiller & D. Taphorn; GoogleMaps INPA 34980 , 1, 61.1mm SL, Pirara River , Takutu-Branco drainage , 40 km N of Lethem, 03º37’17.3"N 59º40’29.4"W, 3 Feb 2009, H. López-Fernández, C. Bernard, K. Winemiller & D. Taphorn; GoogleMaps ROM 85721 , 11, 16.2-55.6 mm SL (1, 38.0 mm SL), Pirara River , Takutu-Branco drainage , 03º37’29”N 59º40’38”W, 4 Feb 2009, H. López-Fernández, R. King, D. Bloom & D. Taphorn; GoogleMaps INPA 34979 , 4, 45.5 to 55.4mm SL, Pirara River , Takutu-Branco drainage , 03º37’29"N 59º40’38"W, 4 Feb 2009, H. López-Fernández, K. Winemiller, R. King, D. Bloom & D. Taphorn; GoogleMaps ROM 85751 , 8. 27.1-82.0 mm, Sawariwau River , Takutu-Branco drainage , at Potarinao road crossing, 03º02’22”N 59º45’41.6”W, 1 Feb 2009, H. López-Fernández, C. Bernard, K. Winemiller & D. Taphorn; GoogleMaps ANSP 185172 , 3, 34.4-85.6 mm SL, Kuyuwini River, Essequibo drainage , 60.6 km ENE of Kuyuwini Landing, 02º11’35”N 58º42’15”W, 6 Nov 2003, M. H. Sabaj, J. Armbruster & M. Hardman; GoogleMaps ANSP 180671 , 5, 31.2-89.9 mm SL, Essequibo River , 32.9 km SE of the mouth of Kuyuwini River , 02º00’10”N 58º27’51”W, 9 Nov 2003, M. H. Sabaj, J. Armbruster & M. Hardman; GoogleMaps ANSP 177129 , 7, 26.3-101.7 mm SL, Yurie Creek , Essequibo River , 2.0 km upstream from Paddie Rock campsite, 04º42’03”N 58º42’44”W, 26 Nov 1997, C. Watson, D. Torres & M. Captain; GoogleMaps ANSP 177133 , 16, 19.5-108.5 mm SL, Essequibo River , 2.0 km upstream from Paddle rock campsite, 04º42’20”N 58º42’26”W, 25 Nov 1997, C. Watson, D. Torres & E. McBirley; GoogleMaps AUM 45171 , 30, 16.3-39.9 mm SL, Takutu River , rio Branco drainage , 03º36’04”N 59º37’32”W, 29 Nov 2005, L. S. de Souza, N. Lujan, D. Taphorn, J. Hartsell, E. Liverpool & S. Lord; GoogleMaps AUM 38941 , 6, 31.3-95.8 mm SL (1, 95.8 mm SL), Kuyuwini River , Essequibo drainage , 19.5 km W from mouth of river, 02º14’28”N 58º30’03”W, 11 Nov 2003, J. W. Armbruster, M. H. Sabaj, M. Hardman, D. Thomas, N. Lujan & L. S. de Souza; GoogleMaps AUM 38071 , 8, 29.7-109.6 mm SL ( 1, 109.6 mm SL), Kuyuwini River , Essequibo drainage , 15.2 km E of Kuyuwini Landing, 02º03’48”N 59º07’00”W, 5 Nov 2003, J. W. Armbruster, M. H. Sabaj, M. Hardman, D. Thomas, N. Lujan & L. S. de Souza; GoogleMaps AUM 36110 , 2, 72.5-87.5 mm SL, Yuora River , Takutu-Branco drainage , 6.7 km NE of Karasabai, 04º03’14”N 59º29’07”W, 31 Oct 2002, J. W.Armbruster, M. H. Sabaj, C.Allison, M. Thomas, C. Chin, D. Arjoon & L. Atkinson; GoogleMaps AUM 48715 , 4, 66.3-116.6 mm SL (2, 100.8- 116.6 mm SL), Aruwa Falls , Rupununi River , Essequibo drainage , 03º30’07”N 59º20’22”W, 21 Nov 2007, L. S. de Souza, D. Taphorn, J. Baskin, T. Geerinckx & J. Hwan; GoogleMaps AUM 38827 , 3, 33.9-88.5 mm SL (1, 88.5 mm SL), Kuyuwini River , Essequibo drainage , at Kuyuwini Landing, 02º05’55”N 59º14’58”W, 14 Nov 2003, J. W. Armbruster, M. H. Sabaj, M. Hardman, D. Arjoon, N. Lujan & L. S. de Souza; GoogleMaps AUM 36111 , 4, 14.9-53.5 mm SL (1, 53.5 mm SL), Rupununi River , Essequibo drainage , 5.9 km WSW of Sand Creek, 02º57’60”N 59º34’10”W, 4 Nov 2002, D. C. Werneke, C. Allison, M. Thomas, C. Chin & D. Arjoon; GoogleMaps AUM 38793 , 5, 29.6-63.1 mm SL (2, 41.5-63.1 mm SL), Kuyuwini River , Essequibo drainage , 32.9 km SE from mouth of river, 02º00’10”N 58º27’51”W, 9 Nov 2003, J. W. Armbruster, M. H. Sabaj, M. Hardman, D. Arjoon, N. Lujan & L. S. de Souza; GoogleMaps AUM 38124 , 3, 29.1-45.0 mm SL (1, 45.0 mm SL), Kuyuwini River , Essequibo drainage , 02º02’51”N 59º00’09”W, 5 Nov 2003, J. W. Armbruster, M. H. Sabaj, M. Hardman, D.Arjoon, N. Lujan & L. S. de Souza; GoogleMaps AUM 48431 , 1, 66.1 mm SL, Rupununi River , Essequibo drainage , 03º39’29”N 59º21’38”W, 9 Nov 2007, L. S. de Souza, D. Taphorn, J. Baskin, T. Geerinckx & J. Hwan; GoogleMaps AUM 36190 , 7, 14.1- 52.9 mm SL (5, 43.5-52.9 mm SL), Pirara, Takutu-Branco drainage , 03º38’55”N 59º41’20”W, 2 Nov 2002, J. W. Armbruster, M. H. Sabaj, M. Thomas & D. Arjoon; GoogleMaps AUM 36112 , 1, 94.9 mm SL (1, 94.9 mm SL), Takutu River , Branco drainage , 2.75 km W of Saint Ignatius, 03º21’18”N 59º49’51”W, 5 Nov 2002, J. W. Armbruster, M. H. Sabaj, D. Werneke, C. Allison, M. Thomas, C. Chin & D. Arjoon; GoogleMaps AUM 48137 , 8, 34.8-75.6 mm SL, (8, 34.8-75.6 mm SL), Pirara River , Takutu-Branco drainage , 03º37’31”N 59º40’34”W, 19 Nov 2007, L. S. de Souza, D. Taphorn, J. Baskin, T. Geerinckx & J. Hwan; GoogleMaps AUM 44709 , 3, 21.9-99.2 mm SL (2, 45.3-99.2 mm SL), Takutu River , Branco drainage , near Lethem, 03º28’14”N 59º48’36”W, 27 Nov 2005, L. S. de Souza, N. Lujan, D. Taphorn, J. Hartsell, E. Liverpool & S. Lord; GoogleMaps AUM 48812 , 2, 42.1-88.3 mm SL, (2, 42.1-88.3 mm SL) Rupununi River , Essequibo Drainage , at Massara Landing, 03º53’42”N 59º17’37”W, 22 Nov 2007, L. S. de Souza, D. Taphorn, J. Baskin, T. Geerinckx & J. Hwan; GoogleMaps AUM 44521 , 4, 12.5-102.5 mm SL (1, 66.7 mm SL), Bununi Creek , Rupununi River , Essequibo drainage , 15.8 km W of Massara, 03º52’10”N 59º26’02”W, 25 Nov 2005, L. S. de Souza, N. Lujan, D. Taphorn, J. Hartsell, E. Liverpool & S. Lord; GoogleMaps AUM 48336 , 4, 62.9-119.8 mm SL (2, 62.9-90.8 mm SL), Rupununi River , Essequibo drainage , at Dadanawa Ranch, 02º49’52”N 59º31’40”W, 14 Nov 2007, L. S. de Souza, D. Taphorn, J. Baskin, T. Geerinckx & J. Hwan; GoogleMaps AUM 38155 , 2, 46.6-106.6 mm SL, ( 1, 106.6 mm), Kuyuwini River , Essequibo drainage , 60.6 km ENE of Kuyuwini Landing, 02º11’35”N 58º42’15”W, 6 Nov 2003, J. W. Armbruster, M. H. Sabaj, M. Hardman, D. Arjoon, N. Lujan & L. S. de Souza; GoogleMaps AUM 37960 , 4, 50.0- 69.1 mm SL (2, 50.0- 69.1 mm SL), Kuyuwini Landing, 1.14 km upstream from mouth of river, 02º16’02”N 58º20’15”W, 7 Nov 2003, J. W. Armbruster, M. H.Sabaj, M. Hardman, D. Arjoon, N. Lujan & L. S. de Souza; GoogleMaps AUM 39046 , 4, 46.3-80.0 mm SL (3, 55.4-80.0 mm SL), Yukanopito Falls , Kuyuwini River , Essequibo drainage , 01º54’53”N 58º31’14”W, 9 Nov 2003, J. W. Armbruster, M. H. Sabaj, M. Hardman, D. Arjoon, N. Lujan & L. S. de Souza; GoogleMaps AUM 38191 , 2, 30.5-80.4 mm SL (1, 80.4 mm SL), Kuyuwini River , Essequibo drainage , 48.4 km Kuyuwini Landing, 02º03’54”N 58º48’33”W, 9 Nov 2002, J. W. Armbruster, M. H. Sabaj, M. Hardman, D. Arjoon, N. Lujan & L. S. de Souza, GoogleMaps Guyana, Potaro-Siparuni (Region 8): ANSP 177136 , 5, 32.3-65.7 mm SL, Red Hill Creek , Siparuni River , Essequibo drainage , between Levi Falls and Blackwater camp, 04º44’14”N 58º59’17”W, 5 Dec 1997, G. Watkins et al.; GoogleMaps ANSP 177135 , 21, 17.4-81.1 mm SL, Levi Fall , Siparuni River , Essequibo drainage , 04º44’41”N 59º00’18”W, 4 Dec 1997, G. Watkins et al.; GoogleMaps ANSP 177134 , 6, 21.4-80.7 mm SL, Tumble Down Creek, Siparuni River , Essequibo drainage , 04º48’39”N 58º51’11”W, 8 Dec 1997, G. Watkins et al.; GoogleMaps ANSP 177130 , 1, 79.2 mm SL, Water Dog Falls , Burro Burro River , Essequibo drainage , 04º40’48”N 58º50’46”W, 20 Nov 1997, E. McBirney, W. Prince & D. Jaferally; GoogleMaps AUM 50647 , 1, 42.1 mm SL, Essequibo River, at Pisham-Pisham Rapids , 04º25’54”N 58º29’11”W, 4 Dec 2005, L. S. de Souza, N. Lujan, D. Taphorn, J. Hartsell, E. Liverpool & S. Lord; GoogleMaps AUM 28122 , 2, 37.7-44.2 mm SL, Potaro River , Essequibo drainage , 05º18’14”N 59º18’40”W, 25 Oct 1998, L. M. Page, J. Armbruster, M. H. Sabaj, M. Hardman, J. Knouft & W. Prince; GoogleMaps AUM 45333 , 2, 20.6-44.2 mm SL (1, 44.2 mm SL), Essequibo River , 5 Dec 2005, L. S. de Souza, N. Lujan, D. Taphorn, J. Hatsell, E. Liverpool & S. Lord.

Non-type material. Guyana, upper Takutu-upper Essequibo (Region 9): ANSP 179494 , 1, 67.3 mm SL, Takutu River , Branco drainage , 2.75 km W of Saint Ignatius, 03º21’18”N 59º49’51”W, 5 Nov 2002, M. H. Sabaj, J. Armbruster & M. Thomas; GoogleMaps ANSP 179495 , 6, 10.5-39.1 mm SL, Pirara River , Takutu-Branco drainage , 3.5 km NNW of Pirara, 03º38’55”N 59º41’20”W, 2 Nov 2002, M. H. Sabaj, J. Armbruster & M. Thomas; GoogleMaps AUM 46490 , 1, 45.5 mm SL, Manari Creek, Takutu River , rio Branco drainage , 03º27’04”N 59º46’24”W, 28 Nov 2005, L. S. de Souza, N. Lujan, D. Taphorn, J. Hartsell, E. Liverpool & S. Lord; GoogleMaps AUM 44671 , 13, 13.1-51.9 mm SL, Pirara River , Takutu-Branco drainage , at Pirara Ranch, 03º37’31”N 59º40’37”W, 26 Nov 2005, L. S. de Souza, N. Lujan, D. Taphorn, J. Hartsell, E. Liverpool & S. Lord; GoogleMaps AUM 44670 , 1, 70.1 mm SL, Pirara River , Takutu-Branco drainage , Pirara Ranch, 03º37’31”N 59º40’37”W, 26 Nov 2005, L. S. de Souza, N. Lujan, D. Taphorn, J. Hartsell, E. Liverpool & S. Lord; GoogleMaps ANSP 177128 , 6, 25.2-103.2 mm SL (2 c&s), Essequibo River , 04º44’22”N 58º42’23”W, 24 Nov 1997, C. Watson, D. Torres & D. Siegel; GoogleMaps ANSP 185173 , 9, 24.4-80.7 mm SL, Kuyuwini River , Essequibo drainage , 15.2 km E of Kuyuwini Landing, 02º03’48”N 59º07’00”W, 5 Nov 2003, M. H. Sabaj, J. Armbruster & M. Hardman; GoogleMaps ANSP 185171 , 2, 61.4-73.3 mm SL, Kuyuwini River , Essequibo drainage , 48.4 km E of Kuyuwini Landing, 02º03’54”N 58º48’33”W, 6 Nov 2003, M. H. Sabaj, J. Armbruster & M. Hardman; GoogleMaps ANSP 185177 , 1, 60.8 mm SL, Madkauwau Creek , Kuyuwini River , Essequibo drainage , between Kuyuwini Landing and Parabara village, 02º05’48”N 59º14’36”W, 4 Nov 2003, M. H. Sabaj, J. Armbruster & M. Hardman; GoogleMaps ANSP 185176 , 4, 32.4-68.4 mm SL, Kuyuwini River , Essequibo drainage , 1.14 km upstream from confluence with Essequibo River , 02º16’02”N 58º20’15”W, 7 Nov 2003, M. H. Sabaj, J. Armbruster & N. Lujan; GoogleMaps ANSP 180746 , 4, 11.2-55.3 mm SL, Araquai Creek, Rupununi River , Essequibo drainage , 77.3 km SSE of Lethem, 02º45’45”N 59º27’60”W, 15 Nov 2003, M. H. Sabaj, J. Armbruster & M. Hardman; GoogleMaps AUM 47856 , 1, 79.6 mm SL, Rupununi River , Essequibo drainage , at Kwatamang Landing , 03º55’05”N 59º06’02”W, 5 Nov 2007, L. S. de Souza, D. Taphorn, J. Baskin, T. Geerinckx & J. Hwan; GoogleMaps AUM 38096 , 1, 44.6 mm SL, Madkauwau Creek , Kuyuwini River , Essequibo drainage, 02º05’45”N 59º14’28”W, 4 Nov 2003, J. W. Armbruster, M. H. Sabaj, M. Hardman, N. Lujan & L. S. de Souza; GoogleMaps AUM 38978 , 4, 14.8-40.5 mm SL, Araquai Creek , Rupununi River , Essequibo drainage , 02º45’45”N 59º27’60”W, 15 Nov 2003, M. H. Sabaj, M. Hardman, N. Lujan & L. S. de Souza; GoogleMaps Guyana, Potaro-Siparuni (Region 8): ROM 61915 , 1, 15.9 mm, Essequibo River , channel at south end of Cowhead Island , 04º41’57”N 58º41’30”W, 8 Oct 1990, E. Holm, A. Andries, & D. Desrochers, C. Hestick & L. Hately. GoogleMaps

Diagnosis. Guianacara dacrya ( Figs. 2 View Fig and 3a) belongs to the subgenus Guianacara ( Fig. 3 View Fig ) and therefore can be distinguished from G. oelemariensis (subgenus Oelemaria ) by the possession of two supraneural bones, produced dorsalfin lappets and a midlateral bar. Guianacara dacrya can be distinguished from all other species in the subgenus Guianacara by the possession of an infraorbital stripe that progressively fades across the cheek (from just beneath the eye to the dorsal edge of the pre-opercle) in individuals> 45 mm SL, but remains black or dark brown across the preopercle and interopercle ( Figs. 2 View Fig and 3a). In all other species, the infraorbital stripe is continuous throughout ontogeny. The posterior half of the lower pharyngeal jaw toothplate of G. dacrya possesses a dorsally edentulous laminar expansion of the lateral margin that is not present in other species of Guianacara . Guianacara dacrya can be distinguished from G. stergiosi ( Fig. 3c View Fig ), G. sphenozona ( Fig. 3d View Fig ), G. owroewefi ( Fig. 3f View Fig ) and G. geayi ( Fig. 3e View Fig ) by the possession of a thin midlateral bar which covers three scales at its widest point, thinning to 1.5 to 2 scales, vs. never less than 3 scales. Additionally, adult G. dacrya retain the juvenile dark coloration of the 3 anterior dorsal-fin spines and lappets, which is lost in adults of G. geayi and G. sphenozona . Guianacara dacrya can be further distinguished from G. owroewefi and G. sphenozona by the possession of white spots on both the soft and spiny portions of the dorsal-fin. When a midlateral spot is distinguishable in G. dacrya it is small, round and placed on and below the upper lateral line, similar to G. stergiosi . In other species the midlateral spot is large and oval shaped ( G. owroewefi ) or placed on and above the upper lateral line ( G. sphenozona ). Guianacara dacrya can be distinguished from G. stergiosi and G. cuyunii by a larger eye, a shorter and narrower head, shorter pectoral fin and by produced filaments of the anal, dorsal and (occasionally) caudal fins. Adult Guianacara dacrya can be further distinguished from adult G. cuyunii by a distinct midlateral spot, the possession of dusky branchiostegal membranes and a shallower body, and from adult G. stergiosi by a shorter preorbital region and longer pelvic fins.

Description. Measurements are summarized in Table 1 View Table 1 . No apparent sexual dimorphism. Head slightly broader ventrally than dorsally. Lateral profile more convex dorsally than ventrally. Interorbital area flat to slightly convex. Dorsal head profile ascending, convex to insertion of dorsal fin; dorsal-fin base descending, convex; dorsal caudal peduncle straight or slightly concave to caudal-fin base. Ventral head profile descending, straight from lower lip to isthmus, then straight or slightly convex to pelvic-fin insertion; slightly concave to anal-fin insertion; anal-fin base ascending, slightly convex; ventral caudal peduncle straight to caudal fin base. Lips moderately wide. Lower lip fold discontinuous at dentary symphysis. Maxilla reaching to one-third distance between nostril and orbit, ascending premaxillary process nearly reaching anterior border of orbit. Opercle, preopercle, cleithrum, supracleithrum and post-temporal smooth.

E1 25(16), 26*(32); scales between upper lateral line and dorsal-fin 4(7), 4 1/2*(40) anteriorly and 1 1/2 (49) posteriorly. Scales on upper lateral line 16(2), 17*(15), 18(30), 19(2) and lower lateral line 9(15), 10*(24), 11(9). Circumpeduncular scale rows 7 above lower lateral line, 7 below, ctenoid. Scale rows between lateral lines 2. Opercle, subopercle and cheek fully scaled, cycloid or slightly ctenoid; interopercle bare. Occipital and flank scales ctenoid. Single column of postorbital scales, cycloid. Lateral chest scales ctenoid, smaller than flank scales. Dorsal, anal, pectoral and pelvic fins naked; caudal fin with single rows of cycloid scales between rays to one quarter or one third of fin length. Accessory caudal fin extensions of lateral line dorsally between rays D3 and D4 and ventrally between rays V4 and V5.

Dorsal fin XV,9(16), XV,10*(34); anal III,7(11), III,8*(39). Dorsal spines increasing in length from first to 4 th -5 th, decreasing to 8 th -10 th, then relatively straight; membranous lappets behind anterior 11-13 spines, pointed, about one fifth of spine length anteriorly, decreasing posteriorly. Soft portion slightly expanded, pointed, rays 3 and 4 longest, produced into filaments in large individuals, reaching one third of caudalfin length in small individuals, reaching past the caudal fin in large individuals with filaments. Anal fin pointed, rays 3 and 4 longest, produced into filaments in large individuals, reaching one quarter of caudal fin length in small individuals to past caudal fin in large individuals with produced filaments. Caudal fin emarginate, symmetrical; in a few large, very well preserved specimens ( 96.4 to 106.6 mm SL, particularlyANSP 177133) first and second most dorsal caudal-fin rays produced into filaments. Pectoral fin straight along dorsal margin, rounded along caudal and ventral margins; longest at fifth ray, generally not reaching anal-fin insertion, though nearly reaching in a few specimens. Pelvic fin triangular in shape, first soft ray longest, reaching second anal spine to fourth anal ray, sometimes produced into filament.

Hemiseries in outer row of premaxilla with 10 to 13 thin, sharp, slightly recurved, unicuspid teeth, progressively smaller distally from symphysis. Three or four irregular inner rows of smaller, unicuspid teeth, separated from outermost row by a gap. Dentary hemiseries with 19 to 23 teeth in outer row, four inner rows with smaller teeth separated from outermost row by a slight gap. Dentary hemiseries separated by a small symphyseal gap, particularly in two outermost rows.

External rakers on first gill arch: 7(25), 8*(22), 9(2). Gills with narrow skin cover. Lower pharyngeal tooth plate wide, length of bone 66% of width; dentigerous area 74% of width, 75% of length; 22 teeth in posterior row; 8 or 9 in median row. Lateral outer teeth unicuspid, cylindrical with slightly recurved tips, becoming progressively smaller caudally; posteromedial teeth much larger, molariform, unicuspid, with medial cusps slightly curved anteriorly. Posterior half of lateral margin of toothplate with abrupt, wing-like, dorsally edentulous laminar expansion ( Fig. 4 View Fig ). Four tooth plates on fourth ceratobranchial, 4, 7, 7 and 3 teeth respectively from anterior to posterior plates. Vertebrae: 13+14 = 27(4).

Color in alcohol. Base colour yellowish gray to brownish yellow; snout, nape and upper lip of base colour, opercle and subopercle darker in colour. Lower lip, interopercle, lower region of preopercle, chest and lower 2 or 3 flank scale rows from chest to anal or caudal fin base whitish yellow. Branchiostegal membrane same colour as chest in small specimens, becoming progressively duskier in individuals above 40.0 mm SL. Flank scales darker along caudal margin. Spots slightly darker than base colour sometimes present along flank just above lower lateral line, 2-3 posterior to midlateral bar and 1 anterior to midlateral bar; spot anterior to the midlateral bar frequently expanded dorsally to base of dorsal-fin.

Supraorbital stripe on posterior third of orbit, black to dark brown, 2 to 2.5 scales wide, slightly thinner dorsally, slightly caudally directed, 3 to 3.5 scales anterior to dorsal-fin insertion. Infraorbital stripe just posterior to middle of orbit, thinner than supraorbital stripe, descending to caudal edge of interopercle. Infraorbital stripe colour lighter between the orbit and preopercle in specimens> 45 mm SL, becoming progressively fainter and disappearing in larger specimens; always dark on the preopercle and interopercle, sometimes becoming wider and rounder towards the ventral margin of the interopercle, forming a tear-drop shaped mark. Midlateral bar black to dark brown, frequently of uniform intensity, extending between the base of dorsal spines 7-9; the bar is three scales wide at its widest coinciding with upper lateral line, 2.5 to 3 scales wide above upper lateral line to dorsal-fin base, progressively thinning to 1.5 to 2 scales wide below upper lateral line, disappearing ventrally between H3 and H4. Midlateral bar most intense on and below upper lateral line, sometimes forming a midlateral spot 3 scales wide and 2 to 3 scales deep, extending from just above upper lateral line to just above pectoral-fin. Midlateral bar is maintained, even in largest adults (> 100 mm SL) and even if a midlateral spot is evident. Midlateral bar bounded anteriorly and posteriorly by two lighter coloured bars two to three scales in width.

Dorsal-fin dusky with three most anterior spines and associated membranes black in juveniles and most adults, but varying with preservation. Whitish spots on membranes of the soft portion and caudal half of spiny portion of dorsalfin, with white spots either of equal or smaller size than the darker, brownish or gray markings separating them. Whitish dorsal-fin spots arranged in 4 roughly parallel rows. Caudalfin dusky, with small whitish spots on membranes, not forming an obvious pattern. Anal-fin slightly dusky, whitish spots between last 2 or 3 fin rays. Pelvic-fin hyaline or slightly dusky, spine and first ray darker, gray or black. Pectoral-fin hyaline.

Etymology. From the Greek dakryo, to shed tears or weep. In reference to the tear-streaked appearance of the infraorbital stripe. To be regarded as an adjective in feminine form.

Geographic distribution. Guianacara dacrya is known from south-western and central Guyana, as far north as the Potaro River and as far south as the Yukanopita Falls in the Essequibo River and potentially in northern Brazil as far west as the rio Uraricoera ( Fig. 5 View Fig , but see comments). This species is abundant in the Essequibo basin, including the drainages of its main tributaries the Rupununi, Siparuni and Kuyuwini, as well as the Takutu and Ireng drainages in the Branco River basin. Sampling has not been undertaken in the Rewa River, or its tributaries, however it is likely that further field exploration will reveal the presence of G. dacrya in this basin.

Habitat. As all other known species in the genus, Guianacara dacrya is generally found associated with clear water streams with moderate current, but also in seasonally flooded lagoons with no current in the Rupununi savannas. Substrate is usually sandy with nearby large rocks; large numbers of juveniles were observed in river sections formed by mixtures of pebbles and small rocks over sandy bottom, frequently with some leaf litter. Water parameters of localities where G. dacrya was collected showed a temperature range of 24.8-28.5ºC, with relatively high dissolved oxygen levels ( 5.3-6.56 mg /L) and very low conductivity (27.1-34.5 µ S) at localities in the Rupununi and Pirara (Ireng) drainages.